3. Area Rules

3.1 The Two Types of Area Rules

The main concept of area rules is the right of stones to exist on the
board. Area rules are significant in preserving the primitive, most
basic form of go. Even in the study of territory rules, it is important
to know how area rules are formulated, and what light they shed on
various rules problems.

The basic principle of area rules is to compare the number of black and
white stones that can exist on the board. The player who can put more
stones on the board wins. The rules of capture and ko are exactly the
same as in territory rules. The main differences from territory rules
are the following:

(1)

Playing on a neutral point is worth one point.

(2)

Since the question is about the number of stones that can exist, after
all the neutral points have been filled, you can play inside your own
territory without losing anything. Similarly, you have nothing to lose
in playing inside your opponent's territory.

(3)

Prisoners do not count as points.

(4)

Bent four in the corner, three points without capturing, and all other
special positions are resolved through actual play.

The advantage of area rules is that all problems can be resolved
naturally, by playing the position out, without gain or loss to either
side. Formulating a set of area rules is therefore extremely easy, and
the rules can be formulated in a way that leaves no room for theoretical
doubts.

The present ko rule, however, is inadequate. If it is not generalized,
problems can occur at the end of the game. This is an important issue
regarding all types of rules, not just area rules, so we will discuss it
in more detail later.

According to rules that follow the principle of the right of stones to
exist, the final end of a game occurs when the game is continued to the
state shown in Dia. 3-1-5. The game in Dias. 3-1-1 to 3-1-5 was played
on a nine-by-nine board by Go Seigen (9 dan) and Miyamoto Naoki (then 8
dan). Under Japanese rules the game ends at move 80, but Black has to
add stones at 81 and 83 before counting, so Black wins by four points.
Under area rules, note that:

(1)

White 82 is worth one point to White.

(2)

No questions arise about Black's reinforcing at 81 and 83.

(3)

If Black is not allowed to pass at 97, he loses.

Dia. 3-1-1 (1-66)

Dia. 3-1-2 (67-77)ko: 72, 75, 78

Dia. 3-1-3 (78-80)prisoners:black 9, white 6

Dia. 3-1-4 (81-83)prisoners:black 9, white 14

Dia. 3-1-5 (84-96)prisoners:black 9, white 14

Note also that under area rules, Black wins by five points.

Another point to note is that if the circled black stone in Dia. 3-1-5
were replaced with a white stone as in Dia. 3-1-6, then White could play
additional stones at 98 and 100, increasing the number of white stones
on the board by two. That is, the circled black stone in Dia. 3-1-5 has
a value of two points in separating White's groups. In these area rules
there is a bonus for cutting. A point that would connect both sides'
groups is worth four points.

Dia. 3-1-6 (97-100)pass: 97, 99

There is a second type of area rules that compares both the number of
stones and the number of eyes at the end of the game. These rules do
have any cutting bonus. Under these rules it is possible to stop playing
after Dia. 3-1-4, count stones plus territory, and get the same result
as after 96 in Dia. 3-1-5.